A slot antenna includes a metal surface (a ground plane), usually a flat plate, with one or more holes or slots cut out. When the plate is driven as an antenna by a driving frequency, the slot radiates electromagnetic waves in a way similar to a dipole antenna. The shape and size of the slot, as well as the driving frequency, determine the radiation pattern. Often the radio waves are provided by a waveguide, and the antenna includes slots in the waveguide. A slot antenna's advantages are its size, design simplicity, and convenient adaptation to mass production using either waveguide or Printed Circuit (PC) board technology. A first requirement for a slot antenna is an infinitely sized ground plane (conductor) or larger enough size compared to the wavelength (λ). A second requirement is a clearance above and below the ground plane. A third requirement is that the slit/cut/slot is close to half-wavelength to enable radiation (resonance). A fourth requirement is that the feed is positioned to minimize input reflection.
Various devices utilize antennas for wireless communication, such as wireless Access Points (APs), streaming media devices, laptops, tablets, and the like (collectively “wireless devices”). Further, the design trend for such devices is aesthetically pleasing and compact form factors. Since the slot antenna requires clearance in front and at the back of the ground plane and the slot, it is difficult to implement in a device which has a lot of components such as Radio Frequency (RF), power, heatsinks, etc. The required slot length is about λ/2 which for Bluetooth and Wi-Fi is about 60 mm which can be difficult to implement in a compact device. Also, the required optimal feed position is difficult to implement with adjacent parts in a compact design.